I enjoy listening to Car Talk, but never seem to be in the right place to ask this question which has evaded answering by all our mechanics so far. My husband is an artist and we travel in the midwest and in Florida year-round, driving our 2005 Dodge Grand Caravan which we love. We have 118,000 miles on the odometer now and a dent or two but otherwise it’s in great shape. About 2 years ago, we started to notice a high-pitched “whining” noise on our way from Michigan’s Upper Peninsula to Florida. We were driving in the fall in the lovely Smoky Mountains. The weather was hot, the air conditioning on and the van working hard to climb the mountains. We stopped for gas, and then as we started driving again noticed this whining noise when pressing on the accelerator. The noise did not stop until the next morning when the car was completely cool, but started again when it heated up. This whining continues to happen every time the car is driven long distances/gets very warm. Our Michigan mechanic thought it was the alternator and replaced the alternator and coolant tube in 8/2012 but that did not help. Our Florida mechanic flushed the transmission and replaced the fluid in 5/2013 but that did not help. Neither of them could tell us what causes this noise. Should we just continue to drive it this way or go to another shop? My husband is worried that we will be on the road somewhere and it will just QUIT. Help !!!

Last week I had a problem much like this while driving from Seattle to Sacremento. It was caused by the fuel pump. Here are some details:

I didn’t notice if it was related to acceleration, but after a long drive, we could really hear it whine when we stopped at a stoplight or parking lot, and it was also audible over the engine and road noise while driving. After letting it cool overnight, the sound would be gone until another long drive heated it up again. It made this noise several times on the trip south, both in Oregon and in California. We didn’t notice it earlier while in Washington, in spite of a recent trip from Seattle to Mt. Ranier, but that trip was considerably shorter (2 hours vs 6-8) and the weather a bit cooler.

After we reached our destination and the problem reoccured following a shorter drive on a hot day, we had a chance to get underneath and identify the source of the noise. It was coming from the middle of the vehicle (definitely NOT the engine NOR the exhaust pipe) and was loudest on the driver’s side. We found that as soon as the engine shut off, the sound did too, and that when the ignition (but not engine) was turned on again while still hot, it made the noise again for a few seconds and then stopped. We didn’t hear a difference in volume with the gas cap off (as suggested by someone on another forum), but we found that by pressing on the gas tank, the frequency of the whine changed. After our testing and online searching, we had enough information to feel confident in asking the mechanic to replace fuel pump (hate to have that go out in the middle of nowhere). The drive back up the coast was completely whine-free, so I think that did the trick.

When it starts whining, does the pitch of the noise change depending on the engine speed? Will it whine if the engine is revved in neutral, or does the car have to be in gear. If the sound only happens when the van is moving, does the whine change pitch with the engine speed or the speed the vehicle is traveling? Can you describe the sound of the whine by comparing it to something else?

I have a similar whining noise on my 2006 Dodge Caravan with only 36K miles on it. There seems to be no rime or reason as to when this happens. We have taken long trips and short trips, never happens at a specific time. This is so odd as to when the noise occurs. Hear is an example. Road from Palm Coast Fl to Cary, NC no noise. Then on a short trip of 50 miles taking I-95, got to my destination, no problem, drove back same route (4 hours later), no noise on I-95, but once I took the exit and going at a speed of 5-15 MPH engine noise sounded like an old time police siren, for approx. 3 minutes , stopped to let my passenger off, engine still running, and then noise went away driving to my home at an average speed of 45MPH for 15 more minutes. this has happened on 5-6 different occasions. How can anyone diagnose this?? please help